Nonstainable steel alloy



Patented Jan. 1, 1935 UNITED STATES 1,986,208 onsmnunm STEEL Armor Frederick J. Maas, Chicago, 111., assignor of four- No Drawing.

lclaim.

, when'used for the manufacture of apparatuses and devices wherein a" polished non-corroding and non-stainable surface is desired.

Another object of the invention is to provide a steel alloy which when fabricated into apparatuses or devices and/polished will not permit of the impairing of the polished surface thereof or deteriorating when, subjected to the elements or acids, such for example, as vegetable and kindred food acids, saline solutions, copper sulphate, nitric .a'cid, acetic acid and similar chemical media.

Further, it is an object of the invention'to provide an alloy affording a maximum of abrasion and heat resistant. qualities, hence, rendering the same highly efficient for constructional incorporation or usage where such qualities are essential, andwhere, as in the instance of heat subjection and wear coincidentally therewith, a minimum of scaling of thealloy constituted article is imperative.

The invention also comprehends as another of its objects, the provision of a steel alloy which may be satisfactorily cast, drawn, forged or rolled; furthermore, an alloy which when fabricated may be satisfactorily machined and threaded.

In order that the inventionand the characters of production and usage thereof may be clearly understood by those skilled in this particular art, I have in the detailed description hereinafter following, set forth embodiments; thereof.

A typical analysis of a satisflctory embodiment of my improved steel alloy is as follows:

Iron of an amount to complete a 100% mass.

The illustrative formula just odered, constitutes or comprehends one of the approved embodiments of my improved steel alloy.

In combining nickel, manganeseand chromium in the relative proportions indicated in the above teen per cent to Alex J. Prominski, Chicago,

Application August 25, 1933, Serial No. 686,778

formula, I impart a highly stabilized austenitic character to the product, securing thereby effectua-l corrosion resistant qualities, as well as imparting considerable strength to the same.

Through the usage of copper in the alloy, I .1 am enabled to definitely better its malleability and machinability, particularly, as compared with kindred types of standard alloys now prevalent in the trade, and at the same time, by the said addition of. copper in the specified relative proportion, the corrosion resistant properties thereof are not detracted from. In this particular connection, I have found it imperative that care be exercised in order that too great a content of copper shall not be included in the alloy, for in such instances, it will be found that said alloy will become hot short, and oftentimes, as the result thereof, will, by an excessive copper content, be caused to crumble when forged or. similarly treated. To avoid this hot short or brittle condition of the-alloy while it is being worked, the molybdenum content is added to the alloy and has been found to be highly advantageous in this respect, particularly, in such instances where the alloy component manganese materially exceeds the relative mass proportion of 6%. The molybdenum content of the alloy will greatly improve its malleability, and in so doing, will serve to prevent crumbling of the same. Furthermore, by the usage of molybdenum, the grain of the alloywill be rendered very sult; also, its corrosion resistance is improved.

For casting with the improved alloy, I have found it practical andbeneflci'al to run the copper content thereof to a relative proportion as high as 6% for fluidity betterment, though, of course, it is to be understood that this copper content is preferably modulated according to product requirements. Also, in keeping with certain manufacturing requirements for the alloy, its silicon component may be relatively varied or changed, and in some instances, the relative proportion of this particular component may run as high as 2% of the mass, especially, since it will serve to increase the alloy fluidity, and hence, facilitate in making thin castin'gs. Moreover, the silicon component enhances the acid and corrosion resisting qualities of the metal.

The alloymanganese content betters .the malleability thereof, and at the same time, it

fine, and a more homogeneous structure will reaccords to the alloy a luster much higher than that to be found in kindred prevalent metals, likewise, it imparts a highly desirable color tone (white or silvery) thereto.

It is important that the carbon content of the I alloy shall be low, i. e., as indicated in the hereinbefore offered formula. Under some conditions, according to manufacturing requirements, the carbon content of the alloy may be as high as 2% of the mass, but this should be regarded as maximum.

From the foregoing, it will manifest itself to workers skilled in the art that the relative proportions of the improved steel alloy may be varied somewhat, according to the dictates of certain manufacturing requirements, or rather, the character of usage to which the alloy is to be put when fabricated. I, therefore, deem it advisable to' herein set forth a formula to be regarded as indicative of the limits of the respective component elements or constituents of the alloy, as follows:

Per cent Chromium 12 to 30 Manganese A 4 to 12 Nickel to 3% Copper -Q. to 6 Silicon A to 2 Molybdenum to 2 Carbon 0 to 2 Iron of .an amount to complete a 100% mass.

The formulas hereinbefore offered, it shall be understood, set forth typical and satisfactory embodiments of the invention. However, under some manufacturing conditions or requirements to which the improved alloy may be subjected, it may become desirable to eliminate the usage of nickel and to substitute for this component, a quantity of cobalt, the amount of which may vary from 0% to 3% of the mass.

Also, in some instances, a quantity of cobalt may be used in conjunction with a lesser amount of nickel. The usage of cobalt alone, or in conjunction with nickel will serve to impart adequate corrosion resistant properties to the alloy, and likewise, will give a highly desirable color or tone to said alloy. I

In producing or alloying my improved nonstainable steel, I have found it advantageous and preferable to employ calcium carbide as a slag for the melt, rather than the characters of material heretofore used as slags, and particularly, the socalled aluminum slag which has been heretofore widely used in the production of non-stainable steel. ,A slag consisting of calcium carbide, I have found through experimentation, affords a highly efiicient seal, and through its usage, I am enabled to maintain the carbon content of my improved alloy to an extremely low point, hence, assuring eflicient fabrication qualities in the metal.

I claim:

A non-stainable metal alloy consisting of the following elements in' approximately the stated amounts:

The balance of'the alloy being composed substantially of iron.

FREDERICK J. MAAS. 

